Oxa via Amazon offers the Oxa Ultrasonic 4-Liter Cool Mist Humidifier in Blue for $29.99. Coupon code "HG2NISZC" cuts the price to $23.99. With free shipping, that's $12 under our mention of another color from two weeks ago, $26 off, and the lowest price we could find. It features up to 16 hours of continuous operation, dial control, and auto shut-off.